1. Field of the Invention
The present invention relates to a new and useful catalytic process for making alkyltrialkoxysilanes. More particularly, the present invention relates to a new and useful process for making alkyltrialkoxysilanes by a direct reaction of methanol and silicon using a catalyst combination of copper and an alkali carboxylate.
2. Prior Art
U.S. Pat. No. 2,473,260 discloses that at elevated temperatures methanol and elemental silicon react in the presence of copper to produce tetramethoxysilane and hydrogen.
U.S. Pat. No. 4,323,690 discloses that certain tetraalkoxysilanes are produced by heating a lower alcohol, such as methanol and ethanol, and finely divided silicon in the presence of an alkali metal carboxylate catalyst. Small but barely detectable amounts of alkyltrialkoxysilanes are produced by such process and at a very slow rate. No copper catalyst is used in that process.
Methyltrichlorosilane and dimethyldichlorosilane are most important compounds for the production of a wide variety of industrial silicone polymers. Chlorosilanes are hydrolyzable to produce hydrogen chloride which is corrosive to processing equipment. In order to obviate the corrosion problems inherent in the handling of just mentioned chlorosilanes, methyltrimethoxysilane may be used to produce the silicone polymers. Unfortunately, methods used heretofore to make methyltrimethoxysilane are expensive and provide very little yield of the product.
Because of increasing demands for greater availability of methyltrimethoxysilane as an intermediate in the preparation of other organic silicon-containing products, polymers and reagents, and to eliminate the corrosion potential, efforts have been made to find alternative ways for economically producing methyltrimethoxysilane. It is possible to slightly increase the amount of produced methyltrimethoxysilane in the process described in U.S. Pat. No. 4,323,690 by adjusting the reaction conditions used during the reaction between methanol and silicon. Heretofore, these efforts have not been economically successful because extended reaction times at very high pressures are required to shift the reaction to produce only slightly more methyltrimethoxysilane.